This study tests whether the value (0.25, or 1/4) of the interspecific allometric exponent currently thought to be universal for the length–biomass relationship for primary producers (based on data for vascular plants and unicellular microalgae) also applies to macroalgae. Length and dry biomass were measured for four phylogenetically distinct seaweed species, Chondrus crispus Stackhouse, Pterocladiella capillacea (Gmelin) Santelices & Hommersand, Fucus vesiculosus Linnaeus, and Laminaria saccharina (Linnaeus) J.V. Lamouroux, which are representatives of four different orders: Gigartinales and Gelidiales (Rhodophyta) and Fucales and Laminariales (Phaeophyceae). The interspecific exponent found for these seaweeds (0.47) differs significantly from the interspecific “universal” value stated above. The 95% confidence interval for the interspecific exponent for these seaweeds includes 0.5 (or 1/2), a value that is related to an idealized form of bidimensional growth. While vascular plants and unicellular microalgae can be viewed as clearly growing in three dimensions, the studied seaweeds are predominantly flat, which thus seems to explain their divergent allometry. The present study indicates that the comprehensive understanding of allometric trends for primary producers should be based on studies covering the morphological diversity that different groups of primary producers display.
Análise do desempenho fisiológico e da composição química de Pterocladiella capillacea (Rhodophyta, Gelidiales) submetida a diferentes irradiâncias
